Current active balance methods for Battery Management System (BMS) require complicated control and balance circuitry. During the balance process, power must be converted and transferred from a single cell or a group of cells to other group of cells or selected single cell. This process results in significant conversion loss. Further, the circuitry consumes power during standby and operation mode. The circuitry also increases the component count, size and cost. Thus, system reliability and battery life are also reduced.
Prior art solutions to this problem are more elaborate controls that drain more energy exacerbating the problem. See, Balog, R.S., Autonomous Local Control in Distributed DC Power Systems (University of Illinois at Urbana-Champaign, 2006).